The present invention relates to the detection and suppression of periodic signals. More specifically, but without limitation thereto, the present invention relates to a circuit for applying stochastic resonance to bias a nonlinear device with a control signal having a selected amplitude, frequency, and phase to enhance or minimize the response of the device to a periodic signal.
The detection of periodic signals can, under certain conditions, be aided by the presence of controlled amounts of background noise in a nonlinear sensor. The mechanism for this type of signal detection is generally referred to as stochastic resonance. Signals are often encountered that are difficult to detect, even if the frequency is known.
In some cases, it may be desirable to remove certain frequencies from a power spectrum. Filtering is often used for this purpose, however filtering may result in complications, such as raising the noise floor in the output power spectral density. In some applications, such as vibration suppression, an active control scheme may be more effective or practical than filtering.
A continued need therefore exists for a way to enhance or remove periodic signals within a power spectrum.